This no-provisional application claims priority under 35 U.S.C. xc2xa7 119(a) on patent application No. RE99A000096 filed in ITALY on Sep. 28, 1999, which is herein incorporated by reference.
1 . Field of the Invention
The present invention relates generally to the manufacture of sanitary appliances, and more particularly to the casting of appliances of the water closet bowl type.
2.Background Art
In such appliances, the hollow annular upper part of the bowl on which the seat rests is known as the rim.
The rim can be of a closed or open type. In the first case it is in the form of a closed channel in which holes can be provided for feeding the flushing water into the bowl. In the second case it is in the form of a downwardly open channel, ie with its mouth facing the bottom of the bowl.
At the rear of the bowl, the rim is connected to a rear chamber into which the flushing water arrives, and below said connection the bowl has a downwardly extending profiled part forming the central baffle of the seal-trap.
Along the periphery of the rim, at the connection between the water arrival chamber and the downwardly extending wall, there is provided at least one inwardly projecting region or undercut, which gives rise to the problems defined hereinafter.
To manufacture such bowls, casting moulds are known comprising at least two profiled parts formed of a convenient hygroscopic material, for example plaster of Paris, or porous resin.
These can be coupled together to form a casting cavity which is then connected to a specific system for supplying a ceramic material in aqueous suspension, known as slip, and then uncoupled to enable the formed appliance to be removed.
A material layer constituting the wall of the sanitary appliance forms on the permeable hygroscopic portions of the mould.
With each of the mould parts there is associated at least one further part known as an insert, also of hygroscopic material, the purpose of which is to shape the undercuts.
In contrast to the operations involved in coupling and uncoupling the mould parts, which are carried out automatically, the positioning of the at least one insert member prior to complete closure of the mould, and its subsequent removal from the piece formed at the end of the casting cycle, are done manually.
Hence the operators concerned are compelled to carry out repetitive manual operations, which can give rise to problems.
In this respect, these manual operations can result in imprecise positioning of the insert members relative to the respective mould parts, with a consequent reduction in product quality.
In addition, the continuous handling of the insert members can result in their damage, for example chipping due to accidental knocks or falls, with consequent negative repercussions on product quality.
The main object of the present invention is to obviate the aforesaid within the context of a simple, rational and reliable construction.
The mould of the present invention is of the type defined in the introduction, ie comprising at least two profiled parts to be coupled together to define a casting cavity to be filled with slip, and capable of being uncoupled from each other to enable the formed appliance to be removed from the mould, at least one insert member cooperating with the mould parts to form at least one undercut region in said appliance.
According to the present invention, the at least one insert member is associated with one of said mould parts by way of a support unit located inside the casting cavity and comprising two mutually movable members, one of which is fixed and is secured to said one mould part, and the other of which supports the at least one insert member and is able to move between a first position, known as the casting position, in which it arranges the at least one insert member in the configuration which enables it to shape the at least one undercut region, and a second position, known as the removal position, in which it disengages the at least one insert member from said at least one undercut region.
A control device operable from the outside is interposed between said two members.
Preferably, the control device is connected to a service system which provides a suitable operating fluid, such as water, air or hydraulic oil under pressure.
Specifically, the control device comprises a variable volume chamber which is constructed of an elastically deformable material and is of flat shape with its opposing parallel faces secured to said two members.
When said pressurized fluid is fed into said chamber, the at least one insert is made to assume the casting position, or the removal position, whereas when the fluid is discharged from it the elasticity of its walls results in the at least one insert being made to assume the removal position, or the casting position.
Means cooperating with the elastically deformable material of the variable volume chamber are preferably provided to ensure correct return of the movable member into the removal position or into the casting position.
According to a preferred embodiment, the means consist of mechanical elements, such as tension or compression springs interposed between the two component members of the support unit for the at least one insert member.
Alternatively, the means are associated with the system for supplying the pressurized fluid, and consist of a pneumatic vacuum system to be connected to the elastically deformable chamber after discharge of the fluid present therein.
Means are also provided to ensure that the at least one insert member always maintains the same orientation when in the casting position.
Preferably the means are formed such as to enable the casting orientation to be adjusted as required.
Means are also provided to ensure that the at least one insert follows a determined trajectory during the removal stage and always maintains the same orientation when in the removal position.
In a manner totally similar to the action in the casting position, the means are formed such as to enable the removal orientation to be adjusted as required.
According to the present invention, and as described in detail hereinafter, said means are in the form of a series of adjustable push rods interposed between the two members of the support unit.
By virtue of the aforestated solution all the objects of the present invention are attained in that:
the operators are not required to mount and remove the at least one insert member,
there is virtually no risk of damage to the at least one insert member, since it is associated with a mould part which is handled automatically, and
correct positioning of the at least one insert member relative to the component parts of the mould is assured.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.